idct1 Compute the inverse discrete cosine transform of input. Y = idct1(X) Y = idct1(X, N) X: Matrix or integer N: If N is given, then X is padded or trimmed to length N before computing the transform. This function computes the inverse discrete cosine transform of input X. If N is given, then X is padded or trimmed to length N before computing the transform. If X is a matrix, compute the transform along the columns of the the matrix. The transform is faster if X is real-valued and even length.